GB332789A - Variable speed gearing - Google Patents

Abstract

332,789. Soc. d'Exploitation des Brevets Cotal. Feb. 9, 1929, [Convention date]. Variable - speed epicyclic gearing comprises a simple train 3, 7, 8, Fig. 2, of which the planets 7 are carried by a driving-shaft 1, the annulus 3 is fast on the driven shaft 2, and the sun 8 may be clutched solid by an electromagnetic clutch or held fast by a like brake. Magnetic action in the clutch &c. may be replaced at will by the use of keys, and the current may be automatically disconnected when the engine is stopped. Thus armature 9 fast to sun 8 may. be attracted to magnet 4 on annulus 3 for solid driving, or, alternatively, attracted to fixed magnet 10 for yielding an over-drive. The amount of air-gap in the magnets is controlled and adjusted by screws 13 which pass through sockets 12, which in turn screw into the gear-case 11. In an arrangement shown in Fig. 3, this over-driving train 3, 7, 8 may be combined with another train using the same annulus 3 and yielding a speed reduction. When clutch armatures 9, 9a are both attracted outwards, both trains are locked solid and a solid drive results. When armature 9 alone is attracted inwards, train 8, 7, 10 operates, yielding an over-drive. When armature 9<a> alone is attracted inwards, train 10, 7<a>, 8a operates, yielding a reduced drive. When both armatures are attracted inwards, the trains work against one another, yielding a fourth speed. To supersede the magnetic action, keys 14, Figs. 4 and 5, are fitted to slide in the outer edges of the armatures 9. These keys are operated in unison by a striker-ring 1 controlled by an eccentric pin 17 in a hand-operated disc 17<a>. The keys 14 can be engaged with notches 15, 15<1> in the magnets 4, 10 respectively, and the keys 14 are provided each with three notches 21 engaged by a locking spring ball 18. A switch for breaking current when engine shaft 1 stops is shown in Fig. 7. A centrifugal weight 28 slides on a conducting-rod 31, which connects at 32 to the clutch coil. In its outmost position the weight 28 contacts at 25<1> with the end of a conducting strip 25, which extends from a brush contact 23. As shaft 1 slows down, weight 28 is thrust inwards by spring 30 and moves over rheostat wire 26, so that the current weakens, the clutch slips, and the driven shaft moves more slowly. At the inmost position of weight 28 the circuit is broken.